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Modern powder diffraction
2900
Book Reviews
erogenic episodes and changes in relative plate motion. Trumpy presents a model relating along-strike variations in facies belts within the Alps to transtensional development of basins and platforms along a Mesozoic transform boundary that accomm~ated lateral motion between Africa and Eurasia. Armstrong presents an impressive summary of the magmatic history of the Canadian Cordillera based on maps and space-time plots constructed from a geochronometric data base consisting of 3000 isotopic dates. These data help to constrain the timing of terrane accretion and provide a means to compare and contrast subductionrelated magmatic episodes in different sectors of the Circum-Pacific erogenic system. Le Pichon et al. discuss the tectonic development of the Alpine belt in a plate kinematic framework and demonstrate a correlation between predicted relative motions and paleostress trajectories reconstructed from fault populations in the European platform. Their kinematic analysis provides a quantitative estimate of the amount of continental crust that was subducted during continental collision. The final two chapters of the volume are examples of the mechanical approach to understanding the development of mounlain
Phosphate Deposits of the World. ~ol~rn~ 2: Phosphate Rock Resources editedby A. J. G. Notholt, R. P. Sheldon, and D. F. Davidson. Cambridge University Press, 1989, 566p., U.S. $165.00. (ISBN O52 I-30509 8). THREE VOLUMES OF Phosphate Deposits of the World have been
published to date, all of them as an outgrowth of Project 156 of the International Geological Correlation Program (IGCP). Two of the three were arranged upon a p~ncipally ~mtigmphic basis. Volume 1 treats the “Phanerozoic and Cambrian Phosphorites,” and volume 3 is devoted to “Neogene to Modem phosphorites.” In contrast, volume 2 reflects the efforts of Working Group 2 of the project, “International Phosphate Resource Data Base.” In a sense, this is an inventory listing of the phosphate deposits of the world. In spite of the abundance of review papers, and of various sources in which reserves and resources of phosphor&es are listed, this book fills a void which has been felt by anybody seriously interested in any aspect of phosphorites and phosphate deposits. Phosphorus is an essential constituent of plant and animal life. Hence, the application of phosphate fertilizers is an essential step in modern agriculture. Furthermore, the application of phosphorus can not be substituted for by any other commodity. Fortunately, phosphate rock is widely distributed throughout the world both geograpbically and geolo~c~ly. Presently less than a dozen countries account for practically the entire phosphate production of about 134 million tons per year. It is one of the impressive messages of this book that, given adequate technologies and economic conditions, this number may increase many-fold. The 110 participants from 39 countries contributed 93 chapters to the volume. The organization of the book is purely geographic. The major divisions are North America, South America, Africa, the Middle East, Europe, Asia, USSR and the Mongolian Peoples Republic, and Australia, New Zealand, and Oceania. Each major geographic division is preceded by an Introduction. In these the editors present a listing of the resources in the relevant area, a map of their distribution, a review of the major sedimentary stratigraphy. and a general description of the igneous resources. The introductions also
Modern Powder Dzj’iaction edited by David L. Bish and Jeffrey E. Post. Reviews in Mineralogy 20, Mineralogical Society of America, 1989, 369p., US $20.00 (ISBN O-939950-24-3). X-RAY POWDER DIFFRACTION has come a very long way since the days of the DeBye-Schemer camera and the anal~-recoding powder diffractometer. This volume was produced in conjunction with a
belts which has made great strides in recent years. Dahlen and Suppe discuss the critical taper wedge model for fold-thrust belts and accretionary prisms. Molnar and Lyon-Caen analyze the forces associated with the development and support of moun~n belts, including mechanical strength and gravity. Because of the broad scope of the contributions, individuals may find a limited number of papers directly applicable to their own research and may not, therefore, consider it a necessary addition to a personal library. It represents an important resource, however, for anyone wishing to get an excellent sample of modern tectonic methodology. Many of the chapters would make suitable reading assignments for upper-level courses addressing regional geology or the geotectonic evolution of mountain belts. The volume provides a wealth of new tectonic ideas that will serve as models for future investigations of continental deformation.
The Ohio State University Department ~~Ge0log.v and ~inera~og~~ Columbus, OH 43210-1398, USA
Terry J. Wilson
contain general production figures for the years 1977-1987. The book could probably have benefited from a general introducto~ chapter on the world distribution of phosphate rocks. The country by country (or by major deposit) reports include a description of the location, geology, stratigraphy, mineralogy and petrography, age relationships, chemical characteristics (both major elements and traces), and estimates of reserves and resources and production. The editors made an effort to direct the different contributors to standardize their chapters so that for each deposit the essential info~ation can be found in the same order. However, standardization did not succeed in all respects; throughout the volume where concentration of niobium is reported it is referred to as “Nb”; in chap. 10, however, (The Mart&n Carbonatite, Ontario, Canada), the antiquated columbium is revived and listed as “Cb”. In a random sampling of five students and faculty who were asked to identify CbzOs, all were unable to do so. Obviously, even a very con~ientious reviewer could hardly be expected to read the full length of such an essentially encyclopedic work. As with encyclopedias a possible test is to sample several familiar items. If those are accurate, chances are that so is the rest of the book. Upon applying this test to several phosphate deposits with which I am familiar, the volume (authors and editors) passed with flying colors. The information is correct, thorough, and up to date. When reviewing Volume 1 of the sequence (Geochim. Cosmochim. Acta, 53, 2 133-2 134), I remarked that an index would be helpful. Here only an index of deposits/areas is provided. In the case of a book which is essentially a data base, a thorough index, covering a large number of fields is an absolute necessity. The strictly geographical organization of the book is sometimes an obstacle for the reader who is interested in genetic or stratigraphic aspects of phosphate rocks. Only good indexing could help such a reader. In fact, I wonder whether the best way to make such a data base accessible is to release it as a personal computer disk as an appendix to the three volume sequence. The Hebrew University of Jerusalem Department of Geology Institute of Earth Sciences Jerusalem, Israel 91904
Yehoshua Kolodny
short course on modern methods of X-ray powder diffractometry held in November, 1989. In it, the editors “have attempted to (1) provide examples illustrating the state-of-the-art in powder diffraction, with emphasis on applications to geologic materials; (2) describe how to obtain hip-quaIity powder diffraction data; and (3) show how to extract maximum information from available data.” Although high temperature and pressure experiments and texture analysis methods
Book Reviews are not covered, the editors and authors have done a major service to the earth and material sciences communities in putting together this handy and inexpensive guide to modem powder diffraction methods. The first chapter by R. C. Reynolds Jr. is a concise discussion of the physics of powder diffraction which is necemary for understanding the processes and methods to follow. The second chapter by Ron Jenkins is a discussion of instrumentation for X-ray powder diffraction. It begins with a description of camera methods (DeBye-Scherrer, Gandolfi, and Guinier) and powder diffractometer geometries with a discussion of systematic aberrations and the effects of various instrument parameters. Next there is a discussion of X-ray detectors and monochromators. The third chapter, also by Jenkins, is a discussion of experimental procedures and causes of error in X-ray powder studies. The author describes factors influencing d-spacing accuracy, intensity accuracy, the automation of qualitative phase analysis (search-match) procedures, and the use of external and internal standards. The fourth chapter by Bish and Reynolds covers sample preparation for X-ray studies and effects of the various preparation methods on the powder patterns. This chapter includes a discussion of grinding methods and particle size effects, area, thickness and surface effects, extinction and absorption effects. Also discussed are various methods to insure random orientation and maximum preferred orientation methods for the study of clays. The next chapter by Snyder and Bish is a discussion of methods for quantitative phase analysis covering the internal standard method, the reference-intensity ratio method, absorption-diffraction method, and a brief description of full-pattern fitting methods. Chapter 6, by Reynolds covers diffraction by small, disordered crystals and is principally a discussion of particle size and disorder effects in clays. Chapter 7 by Deane Smith is a description of various
Eocene Lake Messel edited by Jens Lorenz Franzen and Walter Michaelis. International Symposium at Frankfurt am Main, April 81 I, 1987. Courier Forschungsinstitute Senckenberg, 1988, 452~. (3924500-44-4).
THE EOCENE
LAKE MESSELlocality has yielded such a rich diversity of plants, vertebrate, and invertebrate animals that resolutions and petitions have been circulated in an attempt to make it a national preserve. In the process it has been saved from becoming a landfill for industrial waste. The related publicity, combined with various books and numerous popular articles depicting the high quality of fossil preservation, has made Messel one of the most famous paleontological sites in the world. The diversity of extinct life is complemented by its exceptional preservation, as seen in a few animals with stomach contents reasonably intact and 48 million-year-old pollen-bearing flowers. Eocene Lake Messel clearly demonstrates that the excellent preservation of past life also can be seen in the geochemistry of this oil shale. Nearly 100 years of mining at Messel left a large pit with exposed fossil-rich oil shales. The original Messel Lake, only a couple of kilometers in diameter, was formed during the lower Middle Eocene. It was part of a larger Rhein valley rift system and its associated volcanic activity. The lithogenesis of the Messel oil shale, presented by Kubanek et al. suggests a basic-volcanic source for the sediments. The argillaceous sediments of Messel, consisting in part of fine clay particles and cryptocrystalline silica, were deposited mainly by rivers in a quiet lake setting that provided ideal conditions for the preservation of animal and plant fossils. Eocene Luke Messel is the product of an international symposium held at the Senckenberg Museum of Natural History, Frankfurt am Main, Germany, in April of 1987. There are 32 papers, contributed by 54 authors. They are divided into four categories: Geology and Geochemistry, Paleobiology and Taphonomy, Plants and Animals, and Comparisons. Important contributions in each of these categories
2901
commercial and noncommercial computer codes that are available for analysis of powder diffraction data. Included are data bases of powder diffraction data, methods for analysis of lattice-spacing versus intensity (d-1) data, procedures for processing of digital diffraction patterns and structure analysis and display. Chapter 8 by Howard and Preston is a discussion of profile fitting methods. The authors discuss various profile shape function, analysis of particle size and strain accommodating an amorphous profile. Chapter 9 by Post and Bish covers Rietveld refinement of crystal structures using powder X-ray diffraction data. Chapter IO is a discussion of synchrotron powder diffraction by L. W. Finger. A synchrotron is a ring-shaped proton accelerator which produces very intense, polychromatic X-rays tangential to the ring. Several experiments using monochromatized radiation or “whitebeam” energy-dispersive X-ray diffraction are described which take advantage of the tunable wave-length or extreme intensity of the synchrotron radiation. Chapter 11by von Dreele is a discussion of neutron powder diffraction methods and covers the instrumentation and methods for both monochromatized reactor sources and pulsed, time-of-flight, polychromatic accelerator neutron sources. Although this reviewer was unable to attend the short course, I have found the volume to be an extremely useful reference in my attempts to implement some of the pattern fitting procedures in our lab. Overall, it is an up-to-date and readable guide to powder diffraction and computer methods for analysis of diffraction data. The volume is well suited for use as a text in graduate courses on powder diffraction methods, and its very modest cost will make it a reference that every serious user of powder diffraction will want to own. Department ofGeologicalSciences University of Colorado Boulder, CO 80309-0250, USA
Joseph R. Smyth
make this a useful book for invertebrate and vertebrate paleontologists, as well as for paleobotanists. Of particular interest, however, are 10 papers whose major themes are the geochemistry of Messel. The analysis of the lithogenesis of inorganic chemicals was accomplished in part with scanning electron microscopy equipped with energy dispersive X-ray fluorescence. Diagenetic alteration of sediments and fossils are presented by Kubanek et al., including the biogenic constituents and organic debris at Messel. Nip et al. emphasize the immaturity of the Messel oil shale and give three pyrolysis products that characterize the insoluble organic matter of the shale. These are phenols from partly degraded woody tissue, straight chain alkenes and alk- l-enes from terrestrial plant cuticle in part, and pristI-ene and prist-2-ene from algal tocopherols. It is clear from the organic geochemical and petrographic analysis of Rullkijtter et al. that the organic matter is mainly from limnic algae and bacteria with some mixture of terrigenous organisms. More than 80% of the organic matter recognized under the microscope has a dominance of Cmethyl steroids as in alginite B. This is also confirmed in the paper by Piittmann and Goth who analyzed the oil shale using scanning electron microscopy (SEM) and gas chromatography-mass spectrometry (GSMS). The abundant chlorococcalean alga Tetraedron dominates repeated bands in the oil shale. The authors suggest that these algaerich (Tetraedron and Botryococcus) bands were produced by seasonal blooms of algae in the ancient lake. Porphyrin sources and various porphyrin degradation pathways are presented by Callot et al. Many intermediate steps in porphyrin degradation have been preserved in the oil shale. Lipid diagenesis of kerogen can provide biomarker information. Zeng et al. present detailed data of the long-chain alkane-diol and alkan-keto- l-01 components of the kerogen. Michaelis et al. describe the major types of organic carbon in the Messel oil shale. Their analysis confirms what others suggest in this volume. They identify dinoflagellate algal blooms, the presence of Archaebacteria (methanogens) in the depositional environment, and some ligninderived phenols from terrestrial organic matter that are used as biomarkers.
Book Reviews
erogenic episodes and changes in relative plate motion. Trumpy presents a model relating along-strike variations in facies belts within the Alps to transtensional development of basins and platforms along a Mesozoic transform boundary that accomm~ated lateral motion between Africa and Eurasia. Armstrong presents an impressive summary of the magmatic history of the Canadian Cordillera based on maps and space-time plots constructed from a geochronometric data base consisting of 3000 isotopic dates. These data help to constrain the timing of terrane accretion and provide a means to compare and contrast subductionrelated magmatic episodes in different sectors of the Circum-Pacific erogenic system. Le Pichon et al. discuss the tectonic development of the Alpine belt in a plate kinematic framework and demonstrate a correlation between predicted relative motions and paleostress trajectories reconstructed from fault populations in the European platform. Their kinematic analysis provides a quantitative estimate of the amount of continental crust that was subducted during continental collision. The final two chapters of the volume are examples of the mechanical approach to understanding the development of mounlain
Phosphate Deposits of the World. ~ol~rn~ 2: Phosphate Rock Resources editedby A. J. G. Notholt, R. P. Sheldon, and D. F. Davidson. Cambridge University Press, 1989, 566p., U.S. $165.00. (ISBN O52 I-30509 8). THREE VOLUMES OF Phosphate Deposits of the World have been
published to date, all of them as an outgrowth of Project 156 of the International Geological Correlation Program (IGCP). Two of the three were arranged upon a p~ncipally ~mtigmphic basis. Volume 1 treats the “Phanerozoic and Cambrian Phosphorites,” and volume 3 is devoted to “Neogene to Modem phosphorites.” In contrast, volume 2 reflects the efforts of Working Group 2 of the project, “International Phosphate Resource Data Base.” In a sense, this is an inventory listing of the phosphate deposits of the world. In spite of the abundance of review papers, and of various sources in which reserves and resources of phosphor&es are listed, this book fills a void which has been felt by anybody seriously interested in any aspect of phosphorites and phosphate deposits. Phosphorus is an essential constituent of plant and animal life. Hence, the application of phosphate fertilizers is an essential step in modern agriculture. Furthermore, the application of phosphorus can not be substituted for by any other commodity. Fortunately, phosphate rock is widely distributed throughout the world both geograpbically and geolo~c~ly. Presently less than a dozen countries account for practically the entire phosphate production of about 134 million tons per year. It is one of the impressive messages of this book that, given adequate technologies and economic conditions, this number may increase many-fold. The 110 participants from 39 countries contributed 93 chapters to the volume. The organization of the book is purely geographic. The major divisions are North America, South America, Africa, the Middle East, Europe, Asia, USSR and the Mongolian Peoples Republic, and Australia, New Zealand, and Oceania. Each major geographic division is preceded by an Introduction. In these the editors present a listing of the resources in the relevant area, a map of their distribution, a review of the major sedimentary stratigraphy. and a general description of the igneous resources. The introductions also
Modern Powder Dzj’iaction edited by David L. Bish and Jeffrey E. Post. Reviews in Mineralogy 20, Mineralogical Society of America, 1989, 369p., US $20.00 (ISBN O-939950-24-3). X-RAY POWDER DIFFRACTION has come a very long way since the days of the DeBye-Schemer camera and the anal~-recoding powder diffractometer. This volume was produced in conjunction with a
belts which has made great strides in recent years. Dahlen and Suppe discuss the critical taper wedge model for fold-thrust belts and accretionary prisms. Molnar and Lyon-Caen analyze the forces associated with the development and support of moun~n belts, including mechanical strength and gravity. Because of the broad scope of the contributions, individuals may find a limited number of papers directly applicable to their own research and may not, therefore, consider it a necessary addition to a personal library. It represents an important resource, however, for anyone wishing to get an excellent sample of modern tectonic methodology. Many of the chapters would make suitable reading assignments for upper-level courses addressing regional geology or the geotectonic evolution of mountain belts. The volume provides a wealth of new tectonic ideas that will serve as models for future investigations of continental deformation.
The Ohio State University Department ~~Ge0log.v and ~inera~og~~ Columbus, OH 43210-1398, USA
Terry J. Wilson
contain general production figures for the years 1977-1987. The book could probably have benefited from a general introducto~ chapter on the world distribution of phosphate rocks. The country by country (or by major deposit) reports include a description of the location, geology, stratigraphy, mineralogy and petrography, age relationships, chemical characteristics (both major elements and traces), and estimates of reserves and resources and production. The editors made an effort to direct the different contributors to standardize their chapters so that for each deposit the essential info~ation can be found in the same order. However, standardization did not succeed in all respects; throughout the volume where concentration of niobium is reported it is referred to as “Nb”; in chap. 10, however, (The Mart&n Carbonatite, Ontario, Canada), the antiquated columbium is revived and listed as “Cb”. In a random sampling of five students and faculty who were asked to identify CbzOs, all were unable to do so. Obviously, even a very con~ientious reviewer could hardly be expected to read the full length of such an essentially encyclopedic work. As with encyclopedias a possible test is to sample several familiar items. If those are accurate, chances are that so is the rest of the book. Upon applying this test to several phosphate deposits with which I am familiar, the volume (authors and editors) passed with flying colors. The information is correct, thorough, and up to date. When reviewing Volume 1 of the sequence (Geochim. Cosmochim. Acta, 53, 2 133-2 134), I remarked that an index would be helpful. Here only an index of deposits/areas is provided. In the case of a book which is essentially a data base, a thorough index, covering a large number of fields is an absolute necessity. The strictly geographical organization of the book is sometimes an obstacle for the reader who is interested in genetic or stratigraphic aspects of phosphate rocks. Only good indexing could help such a reader. In fact, I wonder whether the best way to make such a data base accessible is to release it as a personal computer disk as an appendix to the three volume sequence. The Hebrew University of Jerusalem Department of Geology Institute of Earth Sciences Jerusalem, Israel 91904
Yehoshua Kolodny
short course on modern methods of X-ray powder diffractometry held in November, 1989. In it, the editors “have attempted to (1) provide examples illustrating the state-of-the-art in powder diffraction, with emphasis on applications to geologic materials; (2) describe how to obtain hip-quaIity powder diffraction data; and (3) show how to extract maximum information from available data.” Although high temperature and pressure experiments and texture analysis methods
Book Reviews are not covered, the editors and authors have done a major service to the earth and material sciences communities in putting together this handy and inexpensive guide to modem powder diffraction methods. The first chapter by R. C. Reynolds Jr. is a concise discussion of the physics of powder diffraction which is necemary for understanding the processes and methods to follow. The second chapter by Ron Jenkins is a discussion of instrumentation for X-ray powder diffraction. It begins with a description of camera methods (DeBye-Scherrer, Gandolfi, and Guinier) and powder diffractometer geometries with a discussion of systematic aberrations and the effects of various instrument parameters. Next there is a discussion of X-ray detectors and monochromators. The third chapter, also by Jenkins, is a discussion of experimental procedures and causes of error in X-ray powder studies. The author describes factors influencing d-spacing accuracy, intensity accuracy, the automation of qualitative phase analysis (search-match) procedures, and the use of external and internal standards. The fourth chapter by Bish and Reynolds covers sample preparation for X-ray studies and effects of the various preparation methods on the powder patterns. This chapter includes a discussion of grinding methods and particle size effects, area, thickness and surface effects, extinction and absorption effects. Also discussed are various methods to insure random orientation and maximum preferred orientation methods for the study of clays. The next chapter by Snyder and Bish is a discussion of methods for quantitative phase analysis covering the internal standard method, the reference-intensity ratio method, absorption-diffraction method, and a brief description of full-pattern fitting methods. Chapter 6, by Reynolds covers diffraction by small, disordered crystals and is principally a discussion of particle size and disorder effects in clays. Chapter 7 by Deane Smith is a description of various
Eocene Lake Messel edited by Jens Lorenz Franzen and Walter Michaelis. International Symposium at Frankfurt am Main, April 81 I, 1987. Courier Forschungsinstitute Senckenberg, 1988, 452~. (3924500-44-4).
THE EOCENE
LAKE MESSELlocality has yielded such a rich diversity of plants, vertebrate, and invertebrate animals that resolutions and petitions have been circulated in an attempt to make it a national preserve. In the process it has been saved from becoming a landfill for industrial waste. The related publicity, combined with various books and numerous popular articles depicting the high quality of fossil preservation, has made Messel one of the most famous paleontological sites in the world. The diversity of extinct life is complemented by its exceptional preservation, as seen in a few animals with stomach contents reasonably intact and 48 million-year-old pollen-bearing flowers. Eocene Lake Messel clearly demonstrates that the excellent preservation of past life also can be seen in the geochemistry of this oil shale. Nearly 100 years of mining at Messel left a large pit with exposed fossil-rich oil shales. The original Messel Lake, only a couple of kilometers in diameter, was formed during the lower Middle Eocene. It was part of a larger Rhein valley rift system and its associated volcanic activity. The lithogenesis of the Messel oil shale, presented by Kubanek et al. suggests a basic-volcanic source for the sediments. The argillaceous sediments of Messel, consisting in part of fine clay particles and cryptocrystalline silica, were deposited mainly by rivers in a quiet lake setting that provided ideal conditions for the preservation of animal and plant fossils. Eocene Luke Messel is the product of an international symposium held at the Senckenberg Museum of Natural History, Frankfurt am Main, Germany, in April of 1987. There are 32 papers, contributed by 54 authors. They are divided into four categories: Geology and Geochemistry, Paleobiology and Taphonomy, Plants and Animals, and Comparisons. Important contributions in each of these categories
2901
commercial and noncommercial computer codes that are available for analysis of powder diffraction data. Included are data bases of powder diffraction data, methods for analysis of lattice-spacing versus intensity (d-1) data, procedures for processing of digital diffraction patterns and structure analysis and display. Chapter 8 by Howard and Preston is a discussion of profile fitting methods. The authors discuss various profile shape function, analysis of particle size and strain accommodating an amorphous profile. Chapter 9 by Post and Bish covers Rietveld refinement of crystal structures using powder X-ray diffraction data. Chapter IO is a discussion of synchrotron powder diffraction by L. W. Finger. A synchrotron is a ring-shaped proton accelerator which produces very intense, polychromatic X-rays tangential to the ring. Several experiments using monochromatized radiation or “whitebeam” energy-dispersive X-ray diffraction are described which take advantage of the tunable wave-length or extreme intensity of the synchrotron radiation. Chapter 11by von Dreele is a discussion of neutron powder diffraction methods and covers the instrumentation and methods for both monochromatized reactor sources and pulsed, time-of-flight, polychromatic accelerator neutron sources. Although this reviewer was unable to attend the short course, I have found the volume to be an extremely useful reference in my attempts to implement some of the pattern fitting procedures in our lab. Overall, it is an up-to-date and readable guide to powder diffraction and computer methods for analysis of diffraction data. The volume is well suited for use as a text in graduate courses on powder diffraction methods, and its very modest cost will make it a reference that every serious user of powder diffraction will want to own. Department ofGeologicalSciences University of Colorado Boulder, CO 80309-0250, USA
Joseph R. Smyth
make this a useful book for invertebrate and vertebrate paleontologists, as well as for paleobotanists. Of particular interest, however, are 10 papers whose major themes are the geochemistry of Messel. The analysis of the lithogenesis of inorganic chemicals was accomplished in part with scanning electron microscopy equipped with energy dispersive X-ray fluorescence. Diagenetic alteration of sediments and fossils are presented by Kubanek et al., including the biogenic constituents and organic debris at Messel. Nip et al. emphasize the immaturity of the Messel oil shale and give three pyrolysis products that characterize the insoluble organic matter of the shale. These are phenols from partly degraded woody tissue, straight chain alkenes and alk- l-enes from terrestrial plant cuticle in part, and pristI-ene and prist-2-ene from algal tocopherols. It is clear from the organic geochemical and petrographic analysis of Rullkijtter et al. that the organic matter is mainly from limnic algae and bacteria with some mixture of terrigenous organisms. More than 80% of the organic matter recognized under the microscope has a dominance of Cmethyl steroids as in alginite B. This is also confirmed in the paper by Piittmann and Goth who analyzed the oil shale using scanning electron microscopy (SEM) and gas chromatography-mass spectrometry (GSMS). The abundant chlorococcalean alga Tetraedron dominates repeated bands in the oil shale. The authors suggest that these algaerich (Tetraedron and Botryococcus) bands were produced by seasonal blooms of algae in the ancient lake. Porphyrin sources and various porphyrin degradation pathways are presented by Callot et al. Many intermediate steps in porphyrin degradation have been preserved in the oil shale. Lipid diagenesis of kerogen can provide biomarker information. Zeng et al. present detailed data of the long-chain alkane-diol and alkan-keto- l-01 components of the kerogen. Michaelis et al. describe the major types of organic carbon in the Messel oil shale. Their analysis confirms what others suggest in this volume. They identify dinoflagellate algal blooms, the presence of Archaebacteria (methanogens) in the depositional environment, and some ligninderived phenols from terrestrial organic matter that are used as biomarkers.